The course of the HIV pandemic in Sub-Saharan African has been dramatic and devastating. Cameroon, in Central Africa, rests within this HIV epicenter. Although its prevalence is on the low end of the spectrum among Sub-Saharan African countries, approximately10% of its general population is infected. Molecular epidemiologic research has revealed that HIV genetic diversity in Cameroon, like Central Africa in general, is the greatest observed in the world. The ecological and evolutionary mechanisms that drive this extraordinary genetic diversity remain poorly understood. Perhaps more importantly, the immunological significance of this genetic diversity for HIV vaccine development is entirely unknown. Over the past five years, faculty at the JHU Bloomberg School of Public Health have built a close and productive collaborative relationship with Cameroonian medical and public health leaders on research and control of HIV and AIDS. Are search laboratory has been constructed, equipped, and staffed, and research projects on molecular epidemiology and clinical HIV vaccine testing have been launched. Key collaborators and supported of this effort on the US side include the Walter Reed Army Institute of Research, the Henry M. Jackson Foundation, and the Centers for Disease as well as the National Institutes of Health. Collaborative studies have also been successfully carried out with a major HIV vaccine manufacturer and NGOs. On the Cameroon side key collaborators are at the Ministry of Defense, the Ministry of Health, the National AIDS Program Offices, and the University of Yaounde. This supplemental funding would enable Cameroonian biomedical scientists at these and other institutions to be trained through internet based courses and in-country workshops on clinical vaccine trials courses, short term epidemiology courses at JHU, public health degree programs both at the University of Yaounde and at JHU, and postdoctoral laboratory molecular epidemiology both in-country and at JHU. We are proposing 1 long-term degree trainees, 34 short-term trainees, 11 postdoctoral trainees. We will also offer 3 local in-country training workshops. [unreadable] [unreadable]